Spark plug



Augl 4', 1925. 1,548,556

' F. W. SCHMIDT SPARK FLUG Filed NOV. 30, 1923 Ptened Auge 4, 1925m mman smae FRIEDERICH W. SCHMIDT, OIE LOS ANGELES, CALIFORNIA.

SPA.RK PL'UGr.

Application filed November 30, 1923.

T0 all w7wm z't mag cmwem:

Be it known that I, FRIEDERICII l/V. SCHMIDT, a citizen 0f G-ennany, resicling at Los Angeles, in the couney 0f LosAngeles anal State of California, l1ave invented neW and useful Improvements in Spark Flugs, of Which the following is a specification.

My present invention is a spark plug, ancl lt is an especial object of this invent1on t0 provicle a spark plug Which shall be thoroughly reliable in action, being substantially self-cleaning, ancl capable 0f uniform ancl satisfactory operation even uncler unfavorable conditions 0f temperature 01' pressure.

II: is an object of this invention to provicle a spark plug Wl1iel1 can be reaclily substitutecl f0r such spark plugs as are in eurrent use and which shall loe substantially selfcleaning even When usecl in an interior engine 01 in connection witl1 eo1nparatively heavy oils or uncler ot-her eonclitions such as comrnonly leacl t0 a fouling 01 unreliable action of a spark plug.

Otl1er objects 0f 1ny invention will appear from tl1e following clescrlption of a specific embocliment the1eof, and from ehe appenclecl elai1ns, taken in eonnection witl1 the acco1npanying drawings, in whicl1:

Figure 1 is an elevational view of a spark plug e1nboclying my invention.

Figure 2 is a bottom plan view 0f tl1e same.

Referring t0 tl1e details 0f that specific embocliment of my invention which I have chosen for purposes of illustration, 1 may be the bocly 035 a spark plug, Wl1iel1 1nay be grounclecl by contact with metallie arts 0f an engine, into tlm explosion chamber 0f Wl1ich tl1e threaclecl encl 2 may extencl, the porcelain insulation 3, 01 tl1e like, being proviclecl to prevent contaet 0f tl1e inner eleetroole l, eonneeted with a suitable source 0f current, therewith.

In Order 130 provicle a suitable spark gap between the central terminal 5 0f the inne1 electrocle 4 ancl a cornplemental terminal, i being usual 130 employ eitl1er a single complenaental terminal 01 a plurality of complemental terminals arrangecl in tl1e sa1ne plane, my novel electrole construction comprises the employment of an outer eleetrocle comprising two pairs 01: terminals, the inner 01 nearer pair 6, 6, being shown as in a comn1on plane ancl spaced more Serial N0. 677,789.

widely apart than the seconcl 013 outer pair ofterminals 7, 7, the terminals cf both pairs being sl1own as threacled into 01 oherwise 1igiclly suppornecl fro1n ancl in conduetive contact with the threadecl portion of alle bocly 0f 1ny spark plug.

Alt-hough I have noc been able to satisfy myself as to tl1e theoretical explanation Jf the aclvantages of a spark plug 0f the characte1 herein sl1own and clescribecl, I fincl that lt is not necessary t0 form the lower OI' outer pai1 of terminals 01 highly (1011-- cluctive material, although the inner 01 upper pair 0f terminals, from eithe1 0f which a spark 1nay pass t0 the central electrode even when 1ny spark plug is tested in 01- clinary air, are preferably formecl of the usual concluctive 1naterial. Even when I l1ave experimentally for1necl the lower 01 oufer pair of ter1ninals 7, 7 fro1n i1on wire, I have olotainecl l1ighly aclvantageous re sults, ancl I l1ave not founcl the exaet spae ing 0f the outer terminals relatively t0 one another 01 relatively to the inner ancl highly concluctive terminals to l0e a matter of importance, providecl only that t-he saicl lower 01 outer terminals be spaced apart, suitable relative intervals between all of tl1e ter1ninals' comprising my spark plug be1ng inclicatecl in the drawing, which is drawn to a substantially uniform seale.

l/Vithout attempting to inclieate whether the utility 0f the lower er outer pair of terminals lies primarily in a thennal 01 in an electrical efiect, such as an influence upon the distribution of an electrie charge 01 the characer 01 path 0f a spark passing between one ol the mentionecl terminals ancl the central terminal 5, I n1ay aclcl that highly aclvantageous results herein re ferrecl fio cannot be obtainecl by tl1e use 013 a single overarching wire in place of the two terminals 7 7 ancl also witl1 the placing of the lower or outer termlnals substantially als right angles t0 tl1e inner 01' upper pair 0-f terminals is both advantageous ancl convenient, although a sligl1t variation in the angular relationships ofthe respective pairs of terminals may be reg'arcled as immaterial.

Although it has heretofore been recog nizecl that there are aclvantages in the employ1nent of DWO 01 more ter1ninals arrangecl in a common plane and at substantially unL for1n distances from a central electrode, 0ne

known type 0f spark plug being provided with a central electrode and three cooperating terminals arranged radially thereabout, I rega1d 1ny described arrangement of two pairs of electrodes arranged at diiferent levels as superior to known electrodes not only in permitting 21 spark t0 pass alternatively between a central eleetrode and any 0ne of a plurality 0f cooperating termina'ls symmetrically arranged, but also'in producing 21 substantially new selfcleaning effect which is 0f the highesc importance in'the burning of low-gmde 0ils 01' during ope1 w tion in old weather 01 under higlrco1npression, botl1 the reliability 015 operation a11d the cmparative avoidance of vibration being very marked in the use oi:' 1ny novel spark plug, in any of tl1e usual types '0'E stutomobile O1 other explosion engines.

Although I have herein deseribe'd laut one eomplete embodiment of 1ny i1wention, it Will be undrsto0d that various feagures thereof 1night be independe1itly employed and also filmt various modifications might be made therein without departure from the spirit and scope 0f 1ny invention, as the same is indicated above an'd' in the followi'ng claims.

VVhat I clai1n is:

l. In a spark plug having a th1ieaded end witl1in Whicl1'is disposed a c ntral electr0de, complemei1tary electrodes projec'ting -irom the face 0f seid threaded end, seid elecfiro'des haVing their ends turned inwardly'befiath the botto1n cf seid cen'tral electrod upo'n parallel but difierent lanes.

2. In a spark pli1g having a threzided end within which is dispose'd a central electfode complementarj elecfirodes seC1i1ed 170 seid threaded end, said electrodes havihg t'h'eir ends turned ir'iwardljbeneath the bottd1n the ends' of each with e'acl1 01;hezr.

of seid central eleetrode upon parallel but diflerent planes.

3. In a spark plu having a threbaded end within Whih is disposed a central electrode, a, pair 015 complementary electrodes projecting from the face 0f said threaded end upon o'pposite sides thereof, said electrodes having their ends turned inwardly beneath the bottom of said cential electrode, and a second pair of electrodes projectingfrom said face and havii1g their ende turned inwardly beneath tl1e ends 015 the first mentioned 13ai1.

4. In a spark plug hzwing a threaded (zncl within' which is disposed a central (aleetto'de, a pair f complementwy electrodeS projecting from the face 0f seid threaded e11d updn opposite sides aliereof said electrode' having *their ends turned inwzirdly beneath the bottom of said central electrode, und a seco1id pa;ir 0f eleetrodes projecting fro1n Said face and having theif e'nds turned inwardly benezith the ende 0f the fifs't inenti0ned pair, pai1". birig in ligr'imeiic 5. In a spark plug having a threadecl ehd With1n Which 1s disp'osed a cenfral electr'ode,

a pai1 (5f compleinentary eledtrodes prjebting from the face 0f, seid tlneaded end u'p0h opposite sides tht'reof, sxid eleotr0des hzW 'the ends 015 the' firSt me11tioi1ed pair being FRIEE-RICH W. SCHMIDT. 

